Method and apparatus for supplying a source gas

ABSTRACT

A method for supplying a source gas to a processing chamber for forming a film on a substrate in the processing chamber includes: heating a carrier gas; bubbling the heated carrier gas in a liquid source disposed in a container to form a vapor source; and supplying a source gas including the vapor source and the heated carrier gas into the processing chamber for forming the film.

RELATED APPLICATION

[0001] The present application claims priority from Korean PatentApplication No. 2002-52021 filed Aug. 30, 2002, the disclosure of whichis hereby incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

[0002] The present invention relates to methods and apparatus forsupplying a source gas, and more particularly to a method for supplyinga source gas by changing a liquid source for forming a film on asubstrate into the source gas, and an apparatus for performing the same.

BACKGROUND OF THE INVENTION

[0003] Generally, semiconductor devices are manufactured by repeatedlyperforming a series of unit processes including a deposition process, aphotolithography process, an etching process, a chemical-mechanicalpolishing process, a cleaning process, a drying process and so on. Inthese unit processes, the deposition process is executed to form a filmon a semiconductor substrate. The deposition process has become ofparticular concern in semiconductor manufacturing technology as thepatterns formed on semiconductor substrates have become minute, and theaspect ratios of the patterns have increased.

[0004] Processes for forming the film on the semiconductor substrateinclude a chemical vapor deposition (CVD) process, a low pressurechemical vapor deposition (LPCVD) process, a plasma enhanced chemicalvapor deposition (PECVD) process, and a metal organic chemical vapordeposition (MOCVD) process. Recently, an atomic layer deposition (ALD)process, a cyclic chemical vapor deposition (CCVD) process, a digitalchemical vapor deposition (DCVD) process, and an advanced chemical vapordeposition (ACVD) process have been used.

[0005] In the process for forming the film, required elements aresupplied to the semiconductor as raw materials for forming the film in agas phase. Thus, a source gas is prepared including reactants comprisingmetal organic precursors and metal halides in addition to the requiredelements, then the source gas is provided to the substrate. To minimizeimpurities in the desired film formed on the substrate using the CVDprocess, organic ligands or halides combined with metal elements amongthe reactants provided to the substrate are decomposed so that theorganic ligands or halides are removed from the substrate. On the otherhand, in the ALD process, the organic ligands or halides are removedfrom the substrate by means of chemical exchange reactions. According tothe ALD process, the required source gases are not mixed in a processingchamber. Rather, the required source gases are successively provided inthe processing chamber using a pulse method. For example, when the filmis formed using a first source gas and a second source gas, the firstsource gas is primarily provided into the processing chamber so that thefirst source gas is chemically absorbed on the substrate. Then, thesecond source gas is provided into the processing chamber such that thesecond source gas is chemically bonded onto the substrate.

[0006] In general, the source gas is evaporated from a liquid source,then is provided into a processing chamber by means of a carrier gas.The main parameters of the process for forming the film includedeposition time, deposition pressure, the supply time of the source gas,the supply time of a purge gas, and the impurity concentration of thesource gas. The impurity concentration of the film, the step coverage ofthe film and the uniformity of the film have become increasinglyimportant in determining the performance of a semiconductor device asthe degree of integration of semiconductor devices has increased.

[0007] U.S. Pat. No. 6,155,540 to Takamatsu et al. discloses anapparatus for supplying a source gas obtained by evaporating a liquidsource. In the apparatus for supplying the source gas, after the liquidsource for the chemical vapor deposition is introduced into a vaporizerby the controlled flow rate, the liquid source is sprayed by anultrasonic atomizing device installed at the inside or the outside ofthe vaporizer. The liquid source is then heated and evaporated by acarrier gas.

[0008] Also, a method is provided for supplying a source gas by bubblinga carrier gas in a liquid source to form the source gas.

[0009]FIG. 1 is a schematic cross-sectional view illustrating aconventional apparatus 100 for supplying a source gas.

[0010] Referring to FIG. 1, a liquid source 10 is disposed in a sealedcontainer 102. A heater 104 is disposed beneath the container 102 forheating the liquid source 10. A carrier gas supplying line 110 isinstalled such that it passes through the upper portion of the container102, and the end portion of the carrier gas supplying line 110 isimmersed in the liquid source 10 in the container 102.

[0011] The liquid source 10 is evaporated by the bubbling of carrier gasprovided from the carrier gas supplying line 110 and heating of theheater 104. The vapor source prepared in the container 102 is introducedinto a processing chamber 140 together with the carrier gas through asource gas supplying line 112.

[0012] Additionally, a purge gas supplying line 114 is connected to theprocessing chamber 140 for supplying a purge gas to purge the processingchamber.

[0013] A chuck 142 for supporting a semiconductor substrate W isinstalled in the processing chamber 140. A heater (not shown) isprovided in the processing chamber 140 to control the temperature of thesemiconductor substrate W. A vacuum pump (not shown) and a pressurecontrol valve (not shown) are connected to the processing chamber 140for adjusting the inner pressure of the processing chamber 140.

[0014] A flow rate control valve 120 is installed in the carrier gassupplying line 110 to control the supply flow rate of the carrier gasprovided into the container 102. The source gas supplying line 112 andthe purge gas supplying line 114 are connected to the processing chamber140 through an integrated gas supply unit (IGS) 130 for controlling thesupply flow rates and supply times of the purge gas and a source gas,the source gas including the vapor source and the carrier gas.

[0015] The source gas is supplied into the processing chamber 140, andis then reacted with the surface of the semiconductor substrate W sothat a film is formed on the semiconductor substrate W. Un-reacted gasand reaction by-products are exhausted from the processing chamber 140by the supply of the purge gas and operation of the vacuum pump.

[0016] When an atomic layer deposition process is performed for formingthe film on the semiconductor substrate W using the apparatus 100 tosupply the source gas, the carrier gas provided into the container 102has a temperature of about room temperature (approximately 23° C.), andthe liquid source 10 in the container 102 is heated to a hightemperature by the heater 104. For example, when titanium alkoxide(Ti(OC₃H₇)₄) is used as the liquid source 10 to form a titanium oxide(TiO₂) film on the semiconductor substrate W, the liquid source 10 isheated to a temperature of above about 80° C. However, the depositionrate of the titanium oxide film is reduced because the temperature ofthe carrier gas is lower than that of the liquid source 10. Thus, thesupply flow rate and the supply time of the carrier gas typically mustbe increased in order to deposit a film having a required thickness.

[0017]FIGS. 2 and 3 are graphs showing the deposition rate of a titaniumoxide film formed by an atomic layer deposition process using a sourcegas provided from an apparatus for supplying source gas as shown in FIG.1.

[0018] Referring to FIGS. 2 and 3, the deposition rate of the titaniumoxide film increases in accordance with the increase in the supply flowrate and the supply time of the carrier gas. The source gas used fordepositing the titanium oxide film includes the titanium alkoxide andozone (O₃), and the carrier and purge gases include argon (Ar) gases. InFIG. 2, the supply time of the carrier gas and purge time areapproximately 2 seconds, respectively. In FIG. 3, the supply flow rateof carrier gas is approximately 500 sccm.

[0019] When the temperature of the liquid source is excessivelyincreased to increase the deposition rate of the titanium oxide film,the liquid source may be thermally decomposed, thereby deterioratingcertain characteristics of the liquid source. Thus, increasing thetemperature of the liquid source to improve the evaporation efficiencyof the liquid source may be disadvantageous. In addition, when thesupply time of the source gas is extended to form a film having thedesired thickness, the supply time of the purge gas typically must beprolonged, also. Hence, the throughput of the deposition process may bereduced in accordance with the supply time extensions of the source andpurge gases.

[0020] Also, the source gas provided through the source gas supplyingline and IGS unit has a temperature lower than that of the liquid sourcedue to the carrier gas while the purge gas provided into the processingchamber through the purge gas supplying line of the IGS unit has atemperature substantially identical to the initial temperature of thecarrier gas. Thus, the temperature of the IGS unit is lower than that ofthe source gas due to the purge gas. As a result, organic metalmaterials included in the source gas passing through the source gassupplying line and the IGS unit may be extracted as solid phases as aresult of the temperature lowering of the IGS unit. The extractedorganic metal materials may move into the processing chamber and serveas impurities in the film formed on the semiconductor substrate.

SUMMARY OF THE INVENTION

[0021] According to embodiments of the present invention, methods andapparatus for supplying a source gas may be provided that improve theevaporation efficiency of a liquid source and prevent or reduce thegeneration of impurities.

[0022] According to method embodiments of the present invention, amethod for supplying a source gas to a processing chamber for forming afilm on a substrate in the processing chamber includes: heating acarrier gas; bubbling the heated carrier gas in a liquid source disposedin a container to form a vapor source; and supplying a source gasincluding the vapor source and the heated carrier gas into theprocessing chamber for forming the film.

[0023] According to further method embodiments of the present invention,a method for supplying a source gas and purge gas to a processingchamber for forming a film on a substrate in the processing chamberincludes: heating a carrier gas; heating a purge gas; heating a liquidsource disposed in a container; bubbling the heated carrier gas in theheated liquid source to form a vapor source; supplying a source gasincluding the vapor source and the heated carrier gas into theprocessing chamber; and supplying the heated purge gas into theprocessing chamber to purge the processing chamber.

[0024] According to embodiments of the present invention, an apparatusfor supplying a source gas and a purge gas to a processing chamber forforming a film on a substrate in the processing chamber, the source gasincluding a carrier gas and a vapor source, is provided. The apparatusincludes a hot gas generator to heat the carrier gas and to heat thepurge gas. The apparatus further includes a container to hold a liquidsource. A carrier gas supplying line is configured to bubble the heatedcarrier gas in the liquid source to form the vapor source. A source gassupplying line is provided to supply the source gas including the vaporsource and the heated carrier gas into the processing chamber. A purgegas supplying line is provided to supply the heated purge gas into theprocessing chamber to purge the processing chamber.

[0025] According to further embodiments of the present invention, anapparatus for supplying a first source gas and a second source gas to aprocessing chamber for forming first and second films, respectively, ona substrate in the processing chamber, the first source gas including afirst carrier gas and a first vapor source, the second source gasincluding a second carrier gas and a second vapor source, the firstvapor source having a first vapor pressure at a prescribed temperatureand the second vapor source having a second vapor pressure at roomtemperature, is provided. The apparatus includes a hot gas generatoroperative to selectively heat the first carrier gas relative to thesecond carrier gas. A first container is provided to hold the firstliquid source, and a second container is provided to hold the secondliquid source. A first carrier gas supplying tube is configured tobubble the first carrier gas selectively heated by the hot gas generatorin the first liquid source to form the first vapor source. A secondcarrier gas supplying tube is configured to bubble the second carriergas in the second liquid source to form the second vapor source. A firstsource gas supplying tube is provided to supply the first source gasincluding the first vapor source and the heated first carrier gas fromthe first container into the processing chamber. A second source gassupplying tube is provided to supply the second source gas including thesecond vapor source and the second carrier gas from the second containerinto the processing chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0026]FIG. 1 is a schematic cross-sectional view illustrating aconventional apparatus for supplying a source gas;

[0027]FIGS. 2 and 3 are graphs showing a deposition rate of a titaniumoxide film as a function of gas flow rate, the film being formed using asource gas provided from the apparatus as shown in FIG. 1;

[0028]FIG. 4 is a flow chart illustrating a method for supplying asource gas according to embodiments of the present invention;

[0029]FIG. 5 is a schematic cross-sectional view illustrating anapparatus according to embodiments of the present invention forperforming the method for supplying the source gas as shown in FIG. 4;and

[0030]FIG. 6 is a schematic cross-sectional view illustrating anapparatus for supplying a plurality of source gases according to furtherembodiments of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE PRESENT INVENTION

[0031] The present invention now will be described more fullyhereinafter with reference to the accompanying drawings, in whichpreferred embodiments of the invention are shown. This invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. In the drawings, the thickness of layers and regionsmay be exaggerated for clarity. Like numbers refer to like elementsthroughout. It will be understood that when an element such as a layer,region or substrate is referred to as being “on” another element, it canbe directly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present.Moreover, each embodiment described and illustrated herein includes itscomplementary conductivity type embodiment as well.

[0032] In accordance with embodiments of the present invention, methodsand apparatus are provided for supplying a source gas to form a film ona substrate. A liquid source in a container is evaporated by bubbling aheated carrier gas through the liquid source to form a vapor source. Theheated carrier gas is mixed with the vapor source evaporated from theliquid source to form the source gas, and the temperature of the sourcegas is thereby increased by the heated carrier gas. The vapor pressureof the vapor source increases according to the temperature increase ofthe source gas, thereby improving the evaporation efficiency of theliquid source. Also, extraction of impurities from the source gas duringthe supply of the source gas may be inhibited or prevented so that thedeposition rate of the film on the substrate can be enhanced, andimpurities in the film are likewise inhibited.

[0033]FIG. 4 is a flow chart illustrating a method for supplying asource gas according to embodiments of the present invention, and FIG. 5is a schematic cross-sectional view illustrating an apparatus forperforming the method for supplying the source gas as shown in FIG. 4,for example.

[0034] Referring to FIG. 4, a carrier gas and a purge gas are heated(step S100). The carrier gas and the purge gas preferably include inertgases such as nitrogen (N₂) gas or argon (Ar) gas, respectively.However, the carrier gas can be the same as the purge gas. That is, whena heated inert gas evaporates a liquid source to transfer the liquidsource into a processing chamber, the heated inert gas is the carriergas. Alternatively, when the heated inert gas purges the processingchamber, the heated inert gas becomes the purge gas.

[0035] The liquid source is disposed in a container and is heated topredetermined temperature (step S102). The step S102 may be performedbefore the step S100, or the steps of S100 and S102 may besimultaneously performed. The heated carrier gas preferably has the sametemperature as the purge gas, and the temperature of the liquid sourcecan be varied in accordance with the type of the liquid source. Theheated carrier gas and the purge gases preferably have temperatures noless than that of the heated liquid source.

[0036] Thereafter, the heated carrier gas is bubbled in the liquidsource to form a vapor source (step S200).

[0037] The heated carrier gas is mixed with the vapor source to form asource gas, and the source gas is then supplied into the processingchamber so that a film is formed on a semiconductor substrate (stepS300). The temperature of the source gas is increased by the heatedcarrier gas. Thus, the vapor pressure of the vapor source is increased,and the evaporation efficiency of the liquid source is also increased.The concentration of the source gas may be increased in accordance withthe augmentation of the evaporation efficiency of the liquid source,thereby improving the deposition rate of the film on the semiconductorsubstrate. The vapor pressure of the vapor source can be selected andvaried depending on the thickness, kind and characteristics of the filmdeposited on the semiconductor substrate.

[0038] Subsequently, the heated purge gas is supplied into theprocessing chamber so that the processing chamber is purged using theheated purge gas. The remaining un-reacted gas and reaction by-productsin the processing chamber are exhausted by the supply of the heatedpurge gas and the operation of a vacuum pump.

[0039] The film formed on the semiconductor substrate may include aninsulation film, a dielectric film, or a metal film, and the liquidsource may include metal halides and/or metal alkoxides. Additionally,the liquid source can include organic metal precursors having variousligand bonds.

[0040] Examples of the metal alkoxides include alkoxides of alkalineearth metals (Group II metals) such as magnesium (Mg), calcium (Ca) orstrontium (Sr), alkoxides of trivalent elements or metals (Group III orXIII metals) such as boron (B), aluminum (Al), or lanthanum (La),alkoxides of quardivalent metals (Group IV or XIV metals) such astitanium (Ti), zirconium (Zr), hafnium (Hf), silicon (Si), germanium(Ge), tin (Sn), or lead (Pb), or alkoxides of pentavalent metals orelements (Group V and XV metals or elements) such as vanadium (V),niobium (Nb), tantalum (Ta), phosphorus (P), arsenic (As), or antimony(Sb).

[0041] Examples of magnesium alkoxide include Mg[OC₂H₄OCH₃]₂. Examplesof the calcium alkoxide include Ca[OC₂H₄OCH₃]₂. Examples of thestrontium alkoxide include Sr[OC₂H₄OCH₃]₂.

[0042] Examples of the boron alkoxide include B[OCH₃]₃, B[OC₂H₅]₃,B[OC₃H₇]₃, or B[OC₄H₉]₃. Examples of aluminum alkoxide includeAl[OC₄H₈OCH₃]₃, Al[OCH₃]₃, Al[OC₂H₅]₃, Al[OC₃H₇]₃, or Al[OC₄H₉]₃.Examples of lanthanum alkoxide include La[OC₂H₄OCH₃]₃, orLa[OC₃H₇CH₂OC₃H₇]₃.

[0043] Examples of titanium alkoxide include Ti[OCH₃]₄, Ti[OC₂H₅]₄,Ti[OC₃H₇]₄, Ti[OC₄H₉]₄, or Ti[OC₂H₅]₂[OC₂H₄N(CH₃)₂]₂. Examples ofzirconium alkoxide include Zr[OC₃H₇]₄, Zr[OC₄H₉]₄, or Zr[OC₄H₈OCH₃]₄.Examples of hafnium alkoxide include Hf[OC₄H₉]₄, Hf[OC₄H₈OCH₃]₄,Hf[OC₄H₉]₂[OC₂H₄N(CH₃)₂]₂, Hf[OC₄H₉]₂[OC₄H₈OCH₃]₂, Hf[OSi(C₂H₅)₃]₄,Hf[OC₂H₅]₄, Hf[OC₃H₇]₄, Hf[OC₄H₉]₄, or HF[OC₅H₁₁]₄. Examples of siliconalkoxide include Si[OCH₃]₄, Si[OC₂H₅]₄, Si[OC₃H₇]₄, Si[OC₄H₉]₄,HSi[OCH₃]₃, HSi[OC₂H₅]₃, Si[OCH₃]₃F, Si[OC₂H₅]₃F, Si[OC₃H₇]₃F, orSi[OC₄H₉]₃F. Examples of germanium alkoxide include Ge[OCH₃]₄,Ge[OC₂H₅]₄, Ge[OC₃H₇]₄, or Ge[OC₄H₉]₄. Examples of tin alkoxide includeSn[OC₄H₉]₄, or Sn[OC₃H₇]₃[C₄H₉]. Examples of lead alkoxide includePb[OC₄H₉]₄, or Pb₄O[OC₄H₉]₆.

[0044] Examples of vanadium alkoxide include VO[OC₂H₅]₃, or VO[OC₃H₇]₃.Examples of niobium alkoxide include Nb[OCH₃]₅, Nb[OC₂H₅]₅, Nb[OC₃H₇]₅,or Nb[OC₄H₉]₅. Examples of tantalum alkoxide include Ta[OCH₃]₅,Ta[OC₂H₅]₅, Ta[OC₃H₇]₅, Ta[OC₄H₉]₅, Ta[OC₂Hs]s[OC₂H₄N(CH₃)₂]₂, orTa[OC₂H₅]₄[CH₃COCHCOCH₃]. Examples of phosphorus alkoxide includeP[OCH₃]₃, P[OC₂H₅]₃, P[OC₃H₇]₃, P[OC₄H₉]₃, PO[OCH₃]₃, PO[OC₂H₅]₃,PO[OC₃H₇]₃, or PO[OC₄H₉]₃. Examples of arsenic alkoxide includeAs[OCH₃]₃, As[OC₂H₅]₃, As[OC₃H₇]₃, or As[OC₄H₉]₃. Examples of antimonyalkoxide include Sb[OC₂H₅]₃, Sb[OC₃H₇]₃, or Sb[OC₄H₉]₃.

[0045] Referring to the apparatus 200 as shown in FIG. 5, a supply gassupplying line 210 is connected to a hot gas generator 212 for supplyingthe supply gas (which is preferably an inert gas) used as the carriergas and the purge gas. The supply gas supplied through the supplyingline 210 may be directed to both a carrier gas supplying line 214 and apurge gas supplying line 224.

[0046] A sealed container 218 receives and holds the liquid source 10for forming the film on the semiconductor substrate W. The carrier gassupplying line 214 connects the hot gas generator 212 and the container218. The carrier gas supplying line 214 passes through the upper portionof the container 218. The end portion of the carrier gas supplying line214 is immersed in the liquid source 10 in the container 218. A flowrate control valve 216 is installed in the carrier gas supplying line214 for controlling the supply flow rate of the carrier gas. A firstheater 220 is installed beneath the bottom face of the container 218 toheat the liquid source 10 disposed in the container 218.

[0047] A source gas supplying line 222 for supplying the source gas 20connects the upper portion of the container 218 and the processingchamber 240 through an IGS unit 230. The purge gas supplying line 224 isconnected to the processing chamber 240 through the IGS unit 230. Thesource gas supplying line 222 includes a first source gas supplying tube222 a and a second source gas supplying tube 222 b. The first source gassupplying tube 222 a connects the container 218 and the IGS unit 230.The second source gas supplying tube 222 b connects the IGS unit 230 andthe processing chamber 240. The purge gas supplying line 224 has a firstpurge gas supplying tube 224 a and a second purge gas supplying tube 224b. The first purge gas supplying tube 224 a connects the hot gasgenerator 212 and the IGS unit 230. The second purge gas supplying tube224 b connects the IGS unit 230 and the processing chamber 240. The IGSunit 230 controls the supply flow rates and supply times of the sourcegas and the purge gas.

[0048] A second heater 232 and a third heater 234 are installed aroundthe second source gas and the second purge gas supplying tubes 222 b and224 b, respectively, adjacent to the processing chamber 240. The heaters232, 234 serve to evenly maintain the temperature of the source gas andthe purge gas supplied into the processing chamber 240. The heaters 232,234 may include respective band heaters, for example.

[0049] A chuck 242 is installed in the processing chamber 240 forsupporting the semiconductor substrate W. A fourth heater (not shown) isinstalled in the processing chamber 240 to heat the semiconductorsubstrate W to the processing temperature. A vacuum pump (not shown) isconnected to one side portion of the processing chamber 240, and apressure control valve (not shown) and a gate valve (not shown) areinstalled in a vacuum line connecting the vacuum pump and the processingchamber 240 so that the inner pressure of the processing chamber 240 canbe controlled.

[0050] After the carrier gas is heated in the hot gas generator 212, theheated carrier gas is supplied through the carrier gas supplying line214 and the flow rate control valve 216. Then, the heated carrier gas isbubbled in the liquid source 10 disposed in the container 218. Thetemperature of the heated carrier gas is preferably equal to or greaterthan that of the heated liquid source 10 because the evaporationefficiency of the liquid source 10 is increased in accordance with theincrease in the temperature of the carrier gas.

[0051] The vapor source vaporized from the liquid source 10 is mixedwith the heated carrier gas bubbled in the liquid source 10, therebyforming the source gas 20. The source gas 20 is supplied into theprocessing chamber 240 through the source gas supplying line 222 and theIGS unit 230. The IGS unit 230 controls the supply flow rate and supplytime of the source gas.

[0052] Meanwhile, the purge gas is provided into the processing chamber240 from the hot gas generator 212 through the purge gas supplying line224 and the IGS unit 230. The IGS unit 230 controls the supply flow rateand supply time of the purge gas.

[0053] The second and the third heaters 232 and 234, installed in thesecond source gas supplying tube 222 b and the second purge gassupplying tube 224 b adjacent to the processing chamber 240, maintainthe temperature of the source gas and the temperature of the purge gas,respectively. That is, the temperatures of the source gas and the purgegas can be controlled by the second heater 232 and the third heater 234at a predetermined temperature.

[0054] The source gas and the purge gas are successively provided intothe processing chamber 240. The source gas provided in the processingchamber 240 forms the film on the semiconductor substrate W. The purgegas provided in the processing chamber 240 purges the processing chamber240. The source gas and the purge gas are repeatedly provided into theprocessing chamber 240 so that a film having a desired thickness isformed on the semiconductor substrate W. Reaction by-products andun-reacted gas are generated during the formation of the film on thesemiconductor substrate W by means of the source gas, and are exhaustedfrom the processing chamber 240 by the purge gas provided into theprocessing chamber 240 and operation of the vacuum pump connected to theprocessing chamber 240.

[0055] The temperatures of the IGS unit 230 and the gas supplying lines222, 224 are constantly maintained during the formation of the film onthe semiconductor substrate W. The source gas and the heated purge gasmaintain the constant temperature of the IGS unit 230, and the secondand the third heaters 232 and 234 constantly maintain the temperature ofthe second source gas tube 222 b and the purge gas supplying tube 224 b.An additional heater can be installed for constantly maintaining thetemperature of the IGS unit 230. In this manner, impurities can beprevented from being extracted from the source gas. The lengths of thefirst source gas tube 222 a and the first purge gas supplying tube 224 amay be sufficiently short so that the temperatures of the source gas andthe heated purge gas are not lowered. However, an additional heater maybe installed where the temperatures of the source gas and the heatedpurge gas are affected by the lengths of the first source gas tube 222 aand the first purge gas supplying tube 224 a.

[0056] A controller 250 is connected to the hot gas generator 212 tocontrol the heating temperature of the inert gas used as the carrier gasand the purge gas. The controller 250 controls the degree of opening ofthe flow control valve 216 so that the controller 250 adjusts the flowrate of the heated carrier gas provided from the hot gas generator 212to the container 218. In addition, the controller 250 is connected tocontrol the heating temperature of the liquid source 10, and isconnected to the second and the third heaters 232 and 234 for constantlymaintaining the temperature of the source gas and the purge gas providedinto the processing chamber 240.

[0057] The IGS unit 230 is connected to the controller 250 to controlthe supply times and the supply flow rates of the source gas and thepurge gas in accordance with a control signal generated from thecontroller 250.

[0058] As shown in FIG. 5, the source gas supplying apparatus 200supplies the processing chamber 240 with one source gas 20. Varioussource gases may be successively used during the formation of the filmon the semiconductor substrate W. Thus, several source gas supplyingapparatus may be required for supplying different source gases. FIG. 6is a schematic cross-sectional view illustrating an apparatus forsupplying a plurality of source gases according to further embodimentsof the present invention.

[0059] The liquid sources for depositing the film on the semiconductorsubstrate W may have characteristics different from one another. Forexample, the titanium alkoxide (Ti[OC₃H₇]₄) forms a source gas at atemperature of approximately 80 to 100° C. while the trimethyl aluminum(Al[CH₃]₃) forms a source gas at room temperature. That is, thetrimethyl aluminum can form a source gas having sufficient concentrationat room temperature while titanium alkoxide does not form a source gashaving sufficient concentration at room temperature. Hence, the liquidsource and the carrier gas should be heated to increase the vaporpressure of the vapor source to a predetermined vapor pressure. Thepredetermined vapor pressure means the vapor pressure at which thesource gas formed from the liquid source has sufficient concentration toobtain a film having the desired thickness. When a titanium oxide filmis formed on a semiconductor substrate, the titanium alkoxide is heatedto have a temperature corresponding to the predetermined vapor pressure,wherein the vapor pressure of the vapor source is previously establishedto obtain a source gas having the concentration for forming the titaniumoxide film having the desired thickness.

[0060] Referring to FIG. 6, different liquid sources 10 and 30 aredisposed in a first container 322 and a second container 324,respectively. While two containers 322, 324 are shown, the number ofcontainers can be varied.

[0061] A first heater 326 is installed beneath the first container 322for heating the first liquid source 10 in the first container 322. Thefirst liquid source 10 received in the first container 322 is changedinto a vapor source during heating the first liquid source 10 at apredetermined temperature while a second liquid source 30 disposed inthe second container 324 is changed into a vapor source at roomtemperature. That is, the first liquid source 10 has the predeterminedvapor pressure at the predetermined temperature, and the second liquidsource 30 has the predetermined vapor pressure at room temperature.

[0062] A supply gas supplying line 310 is connected to a hot gasgenerator 312 for supplying a supply gas, which may be an inert gas suchas a nitrogen gas or an argon gas, to the hot gas generator 312. Thesupply gas supplied through the supplying line 310 may be directed to afirst carrier gas supplying line 314, a second carrier gas supplyingline 318, a first purge gas supplying line 334, and a second purge gassupplying line 336.

[0063] The first carrier gas supplying line 314 connects the hot gasgenerator 312 and the first container 322. The second carrier gassupplying line 318 connects the hot gas generator 312 to the secondcontainer 324. The hot gas generator 312 selectively heats the firstcarrier gas provided into the first container 322. The heated firstcarrier gas is provided into the first container 322 through the firstcarrier gas supplying line 314. The second carrier gas at the roomtemperature is provided into the second container 324 through the secondcarrier gas supplying line 318.

[0064] A first flow rate control valve 316 is installed in the firstcarrier gas supplying line 314 to control the heated first carrier gas.A second flow rate control valve 320 is installed in the second carriergas supplying line 318 to control the second carrier gas at roomtemperature.

[0065] A first vapor source is formed by the bubbling of the heatedfirst carrier gas and the heating of the first heater 326, and is mixedwith the heated first carrier gas bubbled in the heated first liquidsource 10. A first source gas 20 including the first vapor source andthe heated first carrier gas is provided into a processing chamber 350through a first source gas supplying line 328, an IGS unit 349, and athird source gas supplying line 332. A second vapor source is formed bythe bubbling of the second carrier gas with a temperature at roomtemperature and is mixed with the second carrier gas bubbled in thesecond liquid source 30. A second source gas 40 including the secondvapor source and the second carrier gas is provided into the processingchamber 350 through a second source gas supplying line 330, the IGS unit349, and the third source gas supplying line 332. The IGS unit 340controls the supply times and the flow rates of the first and secondsource gases 20 and 40.

[0066] The hot gas generator 312 selectively heats a first purge gas.The first purge gas heated by the hot gas generator 312 is provided fromthe hot gas generator 312 into the processing chamber 350 through thefirst purge gas supplying line 334, the IGS unit 340, and a third purgegas supplying line 338 after the first source gas 20 is supplied. Asecond purge gas having a temperature at room temperature is providedfrom the hot gas generator 312 into the processing chamber 350 throughthe second purge gas supplying line 336, the IGS unit 340, and the thirdpurge gas supplying line 338 after the second source gas 40 is suppliedinto the processing chamber 350. The IGS unit 340 controls the supplytimes and the flow rates of the heated first purge gas and the secondpurge gas having a temperature at room temperature.

[0067] A second heater 342 and a third heater 344 are installed aroundthe third source gas supplying line 332 and the third purge gassupplying line 338, respectively. The second and the third heaters 342and 344 constantly maintain the temperature of the source gas and thepurge gas. A fourth source gas supplying line can be installed betweenthe IGS unit 340 and the processing chamber 350 if the second source gas40 is thermally unstable.

[0068] A controller 360 is connected to the hot gas generator 312 tocontrol the heating temperatures of the first carrier gas and the firstpurge gas, and the controller 360 controls the degree of opening of thefirst and second flow rate control valves 316 and 320. Also, thecontroller 360 is connected to the first heater 326 for controlling theheating temperature of the first liquid source 10, and is connected tothe second and the third heaters 342 and 344 to constantly maintain thetemperature of the first source gas 20 and the first purge gas providedinto the processing chamber 350. The IGS unit 340 is connected to thecontroller 360 to control the supply times and the flow rates of thesource gas and purge gas.

[0069] Hereinafter, a method for forming a titanium oxide film on asemiconductor substrate using an atomic layer deposition process will bedescribed in detail with reference to FIG. 5.

[0070] The carrier gas heated by the hot gas generator 212 is bubbled inthe liquid source 10 disposed in the container 218 to form that thefirst source gas 20. The liquid source 10 received in the container 218is heated to a temperature of approximately 80 to 100° C. Thetemperature of the heated carrier gas is equal to or greater than thatof the heated liquid source 10. Argon gas may be used as the carriergas, and the liquid source may be titanium alkoxide (Ti(OC₃H₇)₄).

[0071] The first source gas 20 formed in the container 218 is providedinto the processing chamber 240 through the IGS unit 230. One portion ofthe titanium alkoxide is chemically absorbed on the semiconductorsubstrate W, and the other portions of the titanium alkoxide are looselyphysically combined with the portion chemically absorbed with thesurface of the semiconductor substrate W.

[0072] Then, the heated purge gas is provided from the hot gas generator212 to the processing chamber 240 through the IGS unit 230. The purgegas includes the same gas (e.g., argon gas) as the carrier gas. Theother portions of the titanium alkoxide not chemically absorbed on thesemiconductor substrate W are removed from the processing chamber 240 bythe supply of the purge gas and operation of the vacuum pump so thatonly the portion of the titanium alkoxide chemically absorbed remains onthe semiconductor substrate W.

[0073] Subsequently, the second source gas is supplied into theprocessing chamber 240. The second source gas may include O₃, a plasmaof O₂, a remote plasma of O₂, or a plasma of N₂ 0. The activated oxygenin the second source gas reacts with the titanium alkoxide chemicallyabsorbed on the semiconductor substrate W such that the atomic layeredtitanium oxide film (TiO₂) is formed on the semiconductor substrate W.

[0074] Then, the purge gas is provided into the processing chamber 240to exhaust the un-reacted second source gas from the processing chamber240. A titanium oxide film having the desired thickness may be formed byrepeatedly performing the above-described steps of supplying the firstsource gas, supplying the purge gas, supplying the second source gas,and supplying the purge gas.

[0075] According to the present invention, the evaporation efficiency ofthe liquid source can be improved because the heated carrier gas isbubbled in the liquid source, thereby augmenting the temperature of thesource gas. That is, the concentration of the source gas can beincreased as the vapor pressure of the vapor source increases, therebyimproving the deposition efficiency of the film formed on thesemiconductor substrate.

[0076] Also, extraction of impurities from the source gas due to anincrease in the temperature of the source gas and the purge gas may beprevented or reduced.

[0077] In the drawings and specification, there have been disclosedtypical preferred embodiments of the invention and, although specificterms are employed, they are used in a generic and descriptive senseonly and not for purposes of limitation, the scope of the inventionbeing set forth in the following claims.

What is claimed is:
 1. A method for supplying a source gas to aprocessing chamber for forming a film on a substrate in the processingchamber, the method comprising: a) heating a carrier gas; b) bubblingthe heated carrier gas in a liquid source disposed in a container toform a vapor source; and c) supplying a source gas including the vaporsource and the heated carrier gas into the processing chamber forforming the film.
 2. The method for supplying a source gas of claim 1,further comprising heating the liquid source.
 3. The method forsupplying a source gas of claim 2, wherein a temperature of the heatedcarrier gas is at least as great as a temperature of the heated liquidsource.
 4. The method for supplying a source gas of claim 1, furthercomprising: heating a purge gas; and supplying the heated purge gas intothe processing chamber to purge the processing chamber after forming thefilm.
 5. The method for supplying a source gas of claim 4, wherein atemperature of the heated carrier gas is substantially the same as atemperature of the heated purge gas.
 6. A method for supplying a sourcegas and a purge gas to a processing chamber for forming a film on asubstrate in the processing chamber, the method comprising: a) heating acarrier gas; b) heating a purge gas; c) heating a liquid source disposedin a container; d) bubbling the heated carrier gas in the heated liquidsource to form a vapor source; e) supplying a source gas including thevapor source and the heated carrier gas into the processing chamber; andf) supplying the heated purge gas into the processing chamber to purgethe processing chamber.
 7. The method for supplying a source gas ofclaim 6, wherein the heated carrier gas and the heated purge gas eachhave temperatures at least as great as a temperature of the heatedliquid source.
 8. An apparatus for supplying a source gas and a purgegas to a processing chamber for forming a film on a substrate in theprocessing chamber, the source gas including a carrier gas and a vaporsource, the apparatus comprising: a) a hot gas generator to heat thecarrier gas and to heat the purge gas; b) a container to hold a liquidsource; c) a carrier gas supplying line configured to bubble the heatedcarrier gas in the liquid source to form the vapor source; d) a sourcegas supplying line to supply the source gas including the vapor sourceand the heated carrier gas into the processing chamber; and e) a purgegas supplying line to supply the heated purge gas into the processingchamber to purge the processing chamber.
 9. The apparatus of claim 8,further comprising a heater to heat the container.
 10. The apparatus ofclaim 8, further comprising an integrated gas supply unit to controlflow rates and supply times of the source gas and the heated purge gas.11. The apparatus of claim 10, wherein: a) the source gas supplying lineincludes: a first source gas supplying tube connecting the container andthe integrated gas supply unit; and a second source gas supplying tubeconnecting the integrated gas supply unit and the processing chamber,and b) the purge gas supplying line includes: a first purge gassupplying tube connecting the hot gas generator and the integrated gassupply unit; and a second purge gas supplying tube connecting theintegrated gas supply unit and the processing chamber.
 12. The apparatusof claim 11, further comprising: a) a first heater connected to thesecond source gas supplying tube to maintain a temperature of the sourcegas provided into the processing chamber through the second source gassupplying tube; and b) a second heater connected to the second purge gassupplying tube to maintain a temperature of the heated purge gasprovided into the processing chamber through the second purge gassupplying tube.
 13. The apparatus of claim 8, further comprising a flowrate control valve installed in the carrier gas supplying line tocontrol a flow rate of the heated carrier gas provided into thecontainer through the carrier gas supplying line.
 14. The apparatus ofclaim 8, further comprising a controller connected to the hot gasgenerator to control a temperature of the heated carrier gas and atemperature of the heated purge gas.
 15. An apparatus for supplying afirst source gas and a second source gas to a processing chamber forforming first and second films, respectively, on a substrate in theprocessing chamber, the first source gas including a first carrier gasand a first vapor source, the second source gas including a secondcarrier gas and a second vapor source, the first vapor source having afirst vapor pressure at a prescribed temperature and the second vaporsource having a second vapor pressure at room temperature, the apparatuscomprising: a) a hot gas generator operative to selectively heat thefirst carrier gas relative to the second carrier gas; b) a firstcontainer to hold the first liquid source; c) a second container to holdthe second liquid source; d) a first carrier gas supplying tubeconfigured to bubble the first carrier gas selectively heated by the hotgas generator in the first liquid source to form the first vapor source;e) a second carrier gas supplying tube configured to bubble the secondcarrier gas in the second liquid source to form the second vapor source;f) a first source gas supplying tube to supply the first source gasincluding the first vapor source and the heated first carrier gas fromthe first container into the processing chamber; and g) a second sourcegas supplying tube to supply the second source gas including the secondvapor source and the second carrier gas from the second container intothe processing chamber.
 16. The apparatus of claim 15, wherein the hotgas generator further selectively heats a first purge gas relative to asecond purge gas, the first purge gas being adapted for purging theprocessing chamber after supply of the first source gas, the secondpurge gas being adapted for purging the processing chamber after supplyof the second source gas.
 17. The apparatus of claim 16, furthercomprising: a) a first purge gas supplying tube to supply the heatedfirst purge gas from the hot gas generator into the processing chamber;and b) a second purge gas supplying tube to supply the second purge gasfrom the hot gas generator into the processing chamber.
 18. Theapparatus of claim 17, further comprising an integrated gas supply unitto control flow rates and supply times of the first source gas, thesecond source gas, the first purge gas, and the second purge gas. 19.The apparatus of claim 15, further comprising a heater to heat the firstcontainer.
 20. The apparatus of claim 15, further comprising: a) a firstflow rate control valve installed in the first carrier gas supplyingtube to control a flow rate of the first carrier gas; and b) a secondflow rate control valve installed in the second carrier gas supplyingtube to control a flow rate of the second carrier gas.